That’s what you took away from the responses? That’s what Nancy Pelosi and her company take away from it too. But you answer your own complaint in the next part of your post:
They don’t care about serial numbers. No law is going to stop the creation of files for 3D printing guns and other weapons because the law means nothing to terrorists, criminals and the insane. If you successfully pass a law to outlaw legal distributors of these files, then only the terrorists, criminals and insane will have them. Those of us who abide by the law will not.
Which one? I got my copy of the Liberator using a torrent. make it illegal, I’d be able to get these files anyway as long as I’m willing to violate the law.
Unfortunately for the government, its attempt to ban these files does actually violate the Constitution. Unfortunately for us, some judges refuse to uphold the Constitution.